This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Depression and cardiovascular disease are often comorbid. Clinical studies report impairment of endothelial functions and increased inflammatory markers (risk factor for cardiovascular disease) in depressed patients. Moreover, structural neuroimaging studies demonstrate that depressed patients have more blood vessel pathology in the frontal white matter than age-matched non-depressed controls. However, no studies of vascular morphology and related growth factors at the microscopic and molecular level have been conducted in depression to date. Our preliminary data on microscopic analysis of vessel number and morphology in postmortem brain tissue reveal significant increases in the density of abnormal vessels in the prefrontal cortex (PFC) in depression. These vascular changes were observed in the same subjects that were used in our previous cell counting studies on reductions in the density of neurons and glial cells. Moreover, our recent gene expression studies in these depressed subjects reveal downregulation of genes for fibroblast growth factor (FGF) and brain-derived neurotrophic factor (BDNF), and rodent studies indicate that these factors are reduced in stressed animals and elevated after treatment with electroconvulsive shock or antidepressants. Thus, we hypothesize that in depression there are alterations in vascular morphology that are associated with deficits in angiogenic and neurotrophic factors as well as pathology of neurons and glial cells in the PFC. We further hypothesize that these changes are due to the depressive disorder itself and not due to treatment with antidepressant medication, therefore they will not be observed in the PFC of monkeys treated with antidepressants. This proposal will be the first quantitative microscopic study of cortical vasculature in major depression. It will likely reveal a link between dysfunctional genes and the expression of angiogenic and neurotrophic factors and the pathology of blood vessels, neurons and glial cells in the prefrontal cortex of depressed individuals. This may reveal novel cellular and molecular targets of antidepressant action and possibly lead to the design of more effective medications for depressed patients with vascular disease.